Usage: 3 forms in 6 verses
Form Translated As     In Verse(s)
μανδύων their uniforms LXX.1Chr.19.4
μανδύασ their uniforms LXX.2Sam.10.4
μανδύαν his uniform LXX.1Sam.17.38LXX.1Sam.18.4
uniform LXX.Judg.3.16LXX.2Sam.20.8

Liddell-Scott-Jones

μανδύας (manduas) a uniform G:N-M

μανδύας [],

(μανδύη [Refs 2nd c.AD+], μανδύαςς, ου, [LXX], or μανδύης [Refs 6th c.AD+], woollen cloak, Persian word accusative to [Refs 4th c.BC+]

LSJ Scripture Refs: LXX.Josh.3.16